I am the author of the eaa-phev.org website, have not worked on that for a while now. Anyway, I have a 2011 Leaf with a 3/12 bars, out of warranty but about to lose the 4th bar. I have an opportunity to purchase a salvaged 2015 battery. No dealer seems willing to swap the packs and reprogram the VCM. Does anyone have any insights they can share regarding how likely it is that I will be able to swap the packs AND/OR Tap the existing pack to add the second?

My primary goal is to just get a better back, secondary goal is to increase total capacity. I think perhaps the best route to try and satisfy goal number one would be to do the opposite of the manual module swap where by I replace the new BMS with my old BMS in the new battery tub and get the adapter hardware to mount it. I'm not entirely sure that the old and new BMS to Module connections are the same between 2011 and 2015.. I presume they are if it is possible to swap the modules, which it sounds like can be done.

collink or Atkam, where did you tap into the contactor power lines to determine the state? The only place I could see doing this is at the round connector at the battery (and I couldn't find a source for that connector to make an in-line adapter) or at the VCM. I'm interested in how you are splicing into those signals, I'd like to do it as low-impact as possible. You also mentioned 3 contactors, are you using 2 main + 1 pre-charge like the main HV battery?

I found this video which has the sequencing, I assume you're using a microcontroller to decode the sequence and determine when it's safe to switch in your pack:

jkenny23 wrote:collink or Atkam, where did you tap into the contactor power lines to determine the state?

It seems like you need to switch out your pack within 200ms before any errors could occur based on some DTCs I found in the service manual.

It looks to me that all you would have to do is drive a pair of contactors as soon as that single main contactor signal is closed. Basically both packs would close their main contactors simultaneously.

Well, that as well as making sure both packs have exactly the same voltage. But as soon as the main contactors open on the Leaf's battery they must do so immediately on the auxiliary pack as well.

It seems like adding more battery to a Leaf could make sense financially. Even if you put this on a trailer, $300 for the trailer, another $100 for the plywood, around $3,000 to $4,000 in Jehu Garcia approved 18650's for another 24-30kWh. $1,200 for a separate BMS and at least another $1,000 for cables, bus bars, connectors, contactors and Arduinos. So at around $6,600 you could have some what close to double the range, as long as you don't burn anything down or get electrocuted in the process.

That beats owning a second vehicle. Well, the total cost of ownership of an average, cheap, used vehicle for 5 years is between $25,000 and $35,000 in the USA. Edmunds TCO calculator guesstimated that my Leaf would cost me $21,000 total cost of ownership for 5 years. Adding a $6,600 battery trailer to a used Leaf wouldn't be as cheap as owning a Ford Fiesta or Mazda2 as an only vehicle, but it would be close. And it would definitely be cheaper than owning a second car.

Of course the more sensible thing to do is patiently wait until Tesla 3's, Chevy Bolts and Gen 2 Leafs can be bought as cheap used cars.

IssacZachary wrote:Of course the more sensible thing to do is patiently wait until Tesla 3's, Chevy Bolts and Gen 2 Leafs can be bought as cheap used cars.

Not to gloat but for those of us lucky enough to live in CO and the Xcel Enery service area that time is now, or last fall.

I paid about $10k for my new model S after all the rebates and tax credits, which is how much I paid for a used VW Passat TDI wagon years ago. I put about 100k miles on that car before selling it to another VW enthusiast who is still driving it (those engines will easily do 400k miles with good maintenance).

In fact, the thing that convinced me to buy the car was that it was cheaper to buy a new one than the used ones I saw on CL. This was my first new car purchase in over 40 years of driving and it shocked my family that I would buy a new car. So far I'm loving it and if (worst case) I lose my 4th bar after 8 years + 1 day of use I'd be happy just buying a new battery at that point.

European new Leaf owner chiming in here - I'm planning to do basically exactly the same mod that ATKAM and Collink did. It really seems to be as simple as hooking up contactors on the RLY V signals on the main battery connector, however, I would like to be extra super sure if there are no other issues to take into account.

I'm an electronics design engineer by trade and would be able to make this mod decently professionally. If ATKAM/Collink are willing to share their notes, I can formalize them and make them into a proper tutorial. I'm also interested to know if it isn't possible to tap off the battery wiring going to the on-board charger, as that is extremely easy to access without the need for a bridge or lift.

The real interesting thing about this is the ability to get additional capacity economically. I can get new 2900mAh (10Wh) 18650s for $2.04/pc, meaning a 96s20p pack would be $3916, doubling the range of the car. At 46g per cell, it's only 88kg or 200lbs of extra weight. Of course, the contactors, wiring, additional firewall, secondary BMS and so on will cost a bit extra on top, but it's significantly less than the price premium of a new 40kWh car.